Ensuring Hardening of Cement Injecting Mortar at the Installation of Grout-injected Micropiles in Permafrost Soils

Abstract

The article deals with the problems of grout-injected (bored) micropiles application in the conditions of permafrost soils. This technology is widely applied in many countries, but the complexity of using the bored micropiles in the conditions of the North lies in ensuring curing of injection mortar when being influenced not only by the negative temperatures of permafrost soil, but also by the negative ambient temperatures. Considering the fact that large-scale development of the Arctic districts of Russia has been initiated, the results of researches in this field are very relevant. For the first time in Yakutsk the technology of the grout-injected micropiles installation has been tested in the amplification of the National library building foundation conducted according to “YakutPNIIS” institute recommendations. The obtained positive results indicate the possibility and effectiveness of their application in the repair of buildings, as well as in the construction of facilities. The article presents the results of the development of injection cement mortars compositions with various additives and the kinetics of their hardening, their approbation in production conditions. The analysis and discussion of the received results confirm that the grout-injected micropiles installation technology in the permafrost conditions can be widely used, promoting an increase in efficiency of new construction and capital repairs of buildings and constructions.